Future of SSL LED lighting is not dim, but it’s flickering

SAN JOSE -- Could Michele Bachmann be right about advanced lighting technology?

Congresswoman Bachmann, former Republican presidential hopeful, has led a campaign for several years in defense of the historic Tom Edison-style incandescent lightbulb, against government pressure for consumers to adopt new, more energy-efficient lighting solutions.

Michael Poplawski, meanwhile, has led one of the government’s teams – at the Pacific Northwest National Laboratory – seeking to solve issues that currently hobble the widespread deployment of LED (Light Emitting Diode) technology, which remains both more expensive and far more efficient than Rep. Bachmann’s beloved tungsten-filament vacuum tube.

“Complicated,” was the commonest word from Poplawski, senior energy engineer at the Portland, Oregon national lab, as he spoke to a session at the DESIGN West conference here Tuesday. He cited numerous complications in the effective use by consumers of LED lighting, and obstacles to reducing costs for the technology.

One of the points Poplawski stressed was that every LED light is a solid-state (SSL) electronic device, while a lightbulb is just, well, a lightbulb. In a presentation that exceeded its planned duration by some 30 minutes, Poplawski dwelt on four problems that his group is working to resolve: flicker, dimmability, power quality, and lifetime limitations linked to “driver reliability.”

Flicker, for example, is not just a relative of the yellow-bellied sapsucker.

Flicker is inherent in every form of electric lighting and it affects everyone differently, according to individual levels of visual sensitivity. “A good chunk of people,” said Poplawski, with a measure of awe, “are seeing things (flicker) at upwards of a thousand hertz.” Flicker’s biggest moment in the limelight occurred in the film, “The Andromeda Strain,” when the stroboscopic flashing of a laboratory light caused one of the characters to suffer an epileptic seizure.

Poplawski mentioned the danger of seizures, and added other side-effects of flicker, including headaches, fatigue, blurred vision, eye strain, reduced visual task performance and distraction on the job.

The good news about LED lighting is that it can reduce flicker, especially compared to standard fluorescent lights. The bad news is a determination by researchers that flicker – which is consistent and predictable in current lighting systems – is more “complicated” in SSL. It tends to vary substantially, both in amplitude and frequency, in various LED bulbs.

Among the solutions Poplawski’s national lab is exploring is the development of LED solutions with minimal flicker, which requires researchers to identify and measure qualitatively (in terms of human reaction) the presence of flicker. In the end, flicker must be measurable in a way that its level can be reported to consumers in a way they’ll understand it.

Among other issues with which Poplawski’s team is wrestling is dimmability. Many homes are equipped with dimmers, virtually all of them designed to dim conventional incandescent and fluorescent lights. The difficulties of designing LED bulbs that react to existing dimming technologies required Poplawski 20 minutes to explain. The adaptation is not easy. Poplawski boiled it down to the fact that consumers don’t know what will happen when they use their twentieth-century dimmer to soften the glare from a post-millenial high-tech bulb.“There’s no predictability today,” said Poplawski. “We operate in a built world with existing products and there, the challenges are significant.”

Similarly difficult is the issue of power quality, the consistency of power flow into the home and its lighting system. “Events” like lightning strikes and power surges can affect LED lights in different ways than they impact older systems. Moreover, the addition of SSL networks to existing power, cable TV and telephone networks – often clustered together on the same utility poles – can result in interference that compromises one or all of the networks.

Poplawski also cited the problem of “driver reliability.” Old-fashioned “drivers” – or lamps -- are often inappropriate vehicles for new-fashioned LED bulbs, causing problems like overheating that can shorten the operating life of the new bulbs. If the bulbs blow out earlier than promised, the advantage of the new technology shrinks significantly.

Indeed, thousands of new bulbs screwed into old sockets and ancient sconces have died well before their predicted demise, souring many consumers, especially the Congresswoman from Minnesota, on the promise of LED lighting. “You don’t know,” lamented Poplawski, “where people are going to stick things.”

In the end, Poplawski found himself suggesting an infrastructure problem similar to that hindering the use of electric automobiles. The installed power-supply base is incompatible with the new forms of power.

President George W. Bush launched the lightbulb wars in America by signing the Energy Independence and Security Act of 2007, which recommended a phase-out of the tungsten-filament bulb. Five years later, however, Rep. Bachmann’s cherished GE Soft-White is still ubiquitous in the land. Apparently, it will remain so for many years to come, glowing wastefully beneath dusty shades in graceful but obsolete drivers (lamps).

What we need here is a new standard for home power supply: a low-voltage DC bus, say 60V, which would be used for lighting and other low-power appliances. AC is essentially pointless once you get down past the 13kV transformer in the street: few of our appliances "need" AC, and most of them have a rectifier right at the front.
With a DC bus in the home, the four problems mentioned would basically go away.

Adam Smith's (AS's) invisible hand of the market does not exist. Once marketers and advertisers pour money into changing our preferences there is no fair dispassionate market left. As for Europe, at least people there don't go broke for medical care, and in some of the countries universities are free or almost free. AS for the larger wattage incandescents, I thought people were working on increasing their efficiencies through heat reflective coatings. If some technology works, then incandescents will be in the market again.

Your liberty to consume petroleum sourced fuel to generate electricity to waste in an inefficient means, becomes my social cost in supporting a global military tasked with securing oil flows around the world. The push for more electrical efficiency in appliances and in lighting and industrially is to reduce how much we depend on petroleum.

Most of the lighting in my house is in the form of recessed ceiling-mounted IC-rated "cans". Unfortunately, most CFL (and I assume, LED) is designed to operate with some air circulation for cooling. In particular, I note that most CFL lighting is designed to "burn base down". I get miserable performance out of R30 CFL reflector flood replacements. In one ceiling, I divided the lamps half-and-half between 65 watt incandescents and the equivalent CFLs. I removed the dimmer because dimmable CFL floods are outrageously priced and very poor in performance. I replaced all of the CFL units three times over the last 5 years; the incandescents are still original.
I'm fairly sensitive to flicker; those LED Chirstmas light strings drive my vision crazy; they're mostly configured as series-strung LEDs in a "self-rectifying" configuration. Horrible, horrible, horrible--the lights look like they're inhabited by crazed ants.
Come up with something cheap, non-toxic and a functional improvement and I'll buy it.

10% of the lights in my house are in closets. They are used for a few seconds at a time, between 0 and a few times a day. Most of these incandescent bulbs are original to when the house was built 25 years ago.
What is the payback period for doubling the efficiency of a bulb that is hardly ever used?
Low initial cost, rapid starting, and good color quality are the only things that are important here, so incandescent is the way to go. Efficiency and extreme long life just don't matter.

Has anyone else noticed the poor reliability of the driver/ballast in today's CFLs? They don't last anywhere near the life of the tube. CFLs contain a small amount of mercury and my bet is most people don't properly recyle them. Due to the shorter than expected life, the landfills will have much more mercury than the initial estimates would have predicted.

Americans have trouble turning off lights. The result has been reducing the waste by making them more efficient.
Michelle doesn't care one way or the other, she just knows a good sound bite when she spots it; but I enjoy her so I send her $25 for campaigning when I can afford it.

I own a business which has been developing different LED lighting applications for several years.
I've never had any issues with 'flicker'!
I have worked on 'retrofit' lighting designs before but the marketplace needs to realise that a fundamental re-design of the light fitting itself is required - how we distribute the light created by the LED/LEDs in a space is the key. Simply replacing a conventional lightbulb with an LED lightbulb does not seem like the ideal solution.
For me, LED driver technology is already mature -people just don't understand how to apply/use it! Plus....expensive!

I just purchased the newest Plilips 60 Watt equivalent LED for $24.95 from Amazon. I bought since it got rave reviews.
I'm extremely happy with bulb so far. It provides a diffuse light pattern very similar to a 60 Watt incandanscent bulb. It's color spectrum seems identical to an incondescent. It dims nicely with no flicker, at least to my eyes. The one disconcerting thing i s that it doesn't get redder as it gets dimmer. I haven't had it long enough to comment on longevity but, at 12 Watts, you can touch the heat sink and not get burned.
It still costs too much for general use but the price should drop significantly with economies of scale.

The article discusses the challenges of LED lighting as a replacement for Edison socket incandescent bulbs -- an application of LEDs that to me seems absurd.
A great deal of efficiency can be gained by simply replacing incandescent bulbs with CFL bulbs, for those who need to adapt into existing old lamp sockets. For those who want LED lighting, here's an idea -- buy new lighting fixtures that are designed for LEDs.
Your mention of the landscape lights is a great example of a good fit between the technology and the application. Flashlights and automotive headlights might be other examples.
In the area of lighting, trying to shove a square peg into a round hole is neither necessary nor wise.